WO2009130689A2 - Encre comprenant des nanostructures - Google Patents

Encre comprenant des nanostructures Download PDF

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Publication number
WO2009130689A2
WO2009130689A2 PCT/IE2009/000016 IE2009000016W WO2009130689A2 WO 2009130689 A2 WO2009130689 A2 WO 2009130689A2 IE 2009000016 W IE2009000016 W IE 2009000016W WO 2009130689 A2 WO2009130689 A2 WO 2009130689A2
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WO
WIPO (PCT)
Prior art keywords
ink
silver
nanoparticles
nanoplates
solution
Prior art date
Application number
PCT/IE2009/000016
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English (en)
Other versions
WO2009130689A3 (fr
Inventor
Margaret Elizabeth Brennan Fournet
Patrick Fournet
Deirdre Marie Ledwith
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National University Of Ireland, Galway
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Publication date
Application filed by National University Of Ireland, Galway filed Critical National University Of Ireland, Galway
Priority to EP09736076A priority Critical patent/EP2279054A2/fr
Priority to US12/736,622 priority patent/US20110039078A1/en
Publication of WO2009130689A2 publication Critical patent/WO2009130689A2/fr
Publication of WO2009130689A3 publication Critical patent/WO2009130689A3/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • B22F1/054—Nanosized particles
    • B22F1/0545—Dispersions or suspensions of nanosized particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • B22F1/054—Nanosized particles
    • B22F1/0553—Complex form nanoparticles, e.g. prism, pyramid, octahedron
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/30—Inkjet printing inks
    • C09D11/32—Inkjet printing inks characterised by colouring agents
    • C09D11/322—Pigment inks
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/52—Electrically conductive inks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0216—Coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24802—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Definitions

  • This invention relates to an ink comprising nanostructures.
  • the invention relates to an ink comprising silver nanoplates.
  • the ink is not aqueous-based; the nanoparticles aggregate in the ink; the nanoparticle size is not well controlled; the formation of agglomerates of nanoparticles lead to dispersion and miscibility difficulties serving to diminish optical and electrical properties; the nanoparticles shape is not controlled.
  • the consequences of this are an inability to control the electrical and optical properties of the ink, and the excessive loading of the ink with metal nanoparticles in order to assure a conductive path on deposition of the ink.
  • the former problem limits the applications of the ink, and the latter problem is a cost issue, especially where the metal in the ink is selected from the precious metals.
  • the invention provides an ink comprising a solution or suspension or mixture of silver nanoplates in a liquid wherein said nanoplates have a distribution of geometric shapes within which one shape geometries selected from the following is predominant:
  • the predominant shape geometry may be triangular plate shaped.
  • the nanoplate may have an aspect ratio between 2 to 25.
  • the liquid may be an aqueous solution, such as water.
  • the liquid may be an organic solvent.
  • the organic solvent may be an alcohol such as ethanol or methanol, or the organic solvent may be dimethylformamide.
  • the liquid may be capable of being readily evaporated from a substrate on which the ink is deposited.
  • the ink may comprise a viscosity lowering agent.
  • the viscosity lowering agent may be a polymer such as polyvinyl alcohol or polyvinyl pyrrolidone.
  • the ink may comprise up to 20% wt of the viscosity lowering agent, such as up to 10% wt of the viscosity lowering agent, for example about 5% wt of the viscosity lowering agent.
  • the ink may comprise a surface tension lowering agent.
  • the surface tension lowering agent may be diethylene glycol.
  • the ink may comprise up to 50% wt of the surface tension lowering agent.
  • the nanoplates may be surface functionalised.
  • the nanoplates may be surface functionalised with a chemical and/or a biological functionalising agent.
  • the functionalising agent may be selected from one or more of: cytidine 5'-diphasphocholine, mercapto-hexanoic acid, and mecapto-benzoic acid.
  • the ink may comprise a stabilising agent, such as trisodium citrate.
  • the ink may have an average resistivity value of up to 2.5 x 10 "4 ⁇ cm.
  • the ink may comprise up to 1.5% wt silver.
  • the ink may comprise up to 30% wt silver.
  • the ink may comprise up to 70% wt silver.
  • the invention further provides a substrate having an ink as described herein delivered or deposited thereon. Part or all of the liquid may be removed after delivery of the ink onto the substrate. A conductive path may be formed after the delivery of the ink onto the substrate. At least some of the nanoplates and the liquid may form the conductive path. Alternatively, some of the nanoplates may form the conductive path by making contact with each other.
  • the invention also provides wires or conductive lines, or tracks made using an ink as described herein.
  • the invention also provides for the use of an ink as described herein in the fabrication of electrical circuits; in the fabrication of photovoltaic cells for solar power or fuel cell applications; in the manufacture of an optical filter.
  • the optical filter may have preferential absorption at certain wavelengths. The wavelengths of preferential absorption may be altered by altering the concentration of nanoplates in the ink. The wavelengths of preferential absorption may be altered by altering the distribution of sizes of nanoplates in the ink. The wavelengths of preferential absorption may be altered by altering the distribution of shapes of nanoplates in the ink.
  • the ink may be used to modify the absorption of radiation, especially of solar radiation, by a photovoltaic cell; to modify the photocurrent generated by a photovoltaic cell under conditions of radiation intensity on the cell; or to induce or enhance a plasmonic response.
  • step (a) or (b) is performed using microfluidic flow chemistry.
  • Silver nanoparticles produced by the process may have an average diameter of between 5 nm and 200 nm such as between 5 nm and 100 nm and a UV-vis spectrum peak in the 420nm to 1 lOOnm region, such as in the 420 nm to 900 nm region.
  • Both steps (a) and (b) may be performed using microfluidic flow chemistry.
  • the silver source may be a silver salt, for example silver nitrate.
  • the silver source may be dissolved in a capping agent solution, for example a capping agent solution selected from the group consisting: Trisodium Citrate, Cetyl-trimethyl-ammonium-bromide.
  • the reducing agent may be selected from the group consisting: sodium borohydride, ascorbic acid.
  • the ratio of silver source : reducing agent may be about 1 : 8.
  • Step (a) may be performed using microfluidic flow chemistry with a flow rate of between 3 ml/min and 10 ml/min for the silver source.
  • Step (a) may be performed using microfluidic flow chemistry with a flow rate of about 1 ml/min for the reducing agent.
  • Step (a) may be performed at O 0 C.
  • Step (b) may further comprise the step of aging the silver seeds.
  • the aging step may comprise: mixing a silver source with a polymeric stabiliser; and
  • the silver source of the aging step may be the same as the silver source used in step (a).
  • the polymeric stabiliser may be water soluble.
  • the polymeric stabiliser may have a molecular weight between 10 kDa and 1300 kDa.
  • the polymeric stabiliser may be selected from one or more of the group consisting: poly(vinyl alcohol), poly(vinyl pyrollidone), poly(ethylene glycol), and poly(acrylic acid).
  • the polymeric stabiliser may be poly(vinyl alcohol).
  • the aging step may further comprise the step of reducing the silver source present in the silver source-polymeric stabiliser-silver seed mixture.
  • the silver source may be reduced by ascorbic acid.
  • Step (b) of the process may be carried out at a temperature of between 10°C to 60°C.
  • step (b) may be carried out at a temperature of 40°C.
  • the nanoparticles produced by the process may be stable in an aqueous solution.
  • the nanoparticles produced by the process may have a colour tunability throughout the visible and near infra red spectrum.
  • the nanoparticles produced by the process may be red in colour in a colloidal aqueous solution.
  • the nanoparticles produced by the process may comprise at least 30% non-spherical shaped nanoparticles.
  • the nanoparticles produced by the process may comprise at least 50% non-spherical shaped nanoparticles. For example, at least 70% non- spherical shaped nanoparticles.
  • the non-spherical shaped nanoparticles may be triangular and/or hexagonal and/or truncated triangular in shape.
  • the nanoparticles produced by the process may have a UV-vis spectral peak in the 345nm region.
  • the nanoparticles produced by the process may have a UV-vis main spectral width FWHM of less than 300nm.
  • a UV-vis main spectral width FWHM of less than 150nm such as a UV-vis main spectral width FWHM of less than 120nm or a UV-vis main spectral width FWHM of less than lOOnm.
  • Microfluidic processes described herein can produce, large volumes of high definition silver nanoparticles with improved properties over the conventional wet chemistry methods including, narrower size distribution, increased presence of shaped nanoparticles, higher uniformity of samples, better and high batch to batch reproducibility.
  • ⁇ UV -Vis Spectrum with main peak in the 420-1 lOOnm region, such as in the 42- - 950 nm region ⁇ FWHM of main UV- Vis spectral peak to be 150nm or less
  • Improvements in the production of silver nanoparticles using the micro fluidics technology described herein include: ⁇ High percentage of triangles vs spheres
  • Properties of high definition silver nanoparticles include:
  • Non aggregated Properties of high definition silver nanoparticles which can be observed in the UV-Vis absorption include:
  • Microfluidics can be used to produce these shaped silver nanoparticles with the important advantage that microfluidics produced a half litre per batch (and is capable of producing several litres per hour) while the wet chemistry method is limited to 100ml production.
  • TEM images confirmed a significant improvement in the size distribution of the microfluidic processor produced silver nanoparticles.
  • Optimisation of the microfluidic processes both the chip and the processor routes will enable the controlled scaled-up production of high quality high definition silver nanoparticles in a range of shapes, sizes, colours, surface chemistries. This technology can be adapted for the scaled up production of a range of high quality nanoparticles.
  • an ink comprising a solution or suspension of nanoparticles in a liquid wherein said nanoparticles have a distribution of geometric shapes within which two or more shape geometries selected from the following are predominant:
  • an ink comprising a solution or suspension or mixture of nanoparticles in a liquid wherein said nanoparticles have a distribution of geometric shapes within which one shape geometry selected from the following is predominant:
  • the liquid may be water or an aqueous solution of other materials in water.
  • the liquid may be an organic solvent.
  • the liquid may be capable of being readily evaporated from a substrate on which the ink is deposited.
  • the nanoparticles may have a preferential distribution of volumes or characteristic length dimensions within a narrow range about a mean volume or mean characteristic length dimension.
  • the nanoparticles may be electrically conducting nanoparticles.
  • the nanoparticles may be metal nanoparticles.
  • the metal may be silver.
  • the liquid may be electrically conducting.
  • at least some of the nanoparticles and the liquid may form a conductive path by making contact with each other and/or with the liquid.
  • the nanoparticles form a conductive path by making contact with each other.
  • the number of nanoparticles per unit volume exceeds the percolation threshold for a specific volume or area geometry into which the ink is to be deposited, such that there exists a high probability (at least greater than 0.99) of said conductive path being formed by contact of some of the conducting particles when the ink is deposited in that particular volume or area geometry.
  • a substrate having an ink described herein delivered or deposited thereon Part or all of the liquid may be removed after delivery of the ink onto the substrate.
  • the morphology of the distribution of the nanoparticles may be changed during or after the delivery of the ink onto the substrate.
  • a conductive path is formed after the delivery of the ink onto the substrate. At least some of the nanoparticles and the liquid may form the conductive path. Alternatively some of the nanoparticles form the conductive path by making contact with each other. In this case the predominant nanoparticle shape is chosen such that the amount of metal per unit volume may be reduced to a minimum while the probability of the existence of a conductive path remains sufficiently close to unity for the reliable industrial application of the ink in applications where a conductive path is required.
  • Wires or conductive lines, or tracks may be made using an ink described herein.
  • the ink may be used in the fabrication of electrical circuits such as in the manufacture of electrical circuits on a board by means of depositing one or more layers of non-conducting material and at least one conducting layer comprised of the said ink.
  • the ink may be used in the fabrication of photovoltaic cells for solar power or fuel cell applications.
  • the ink may be used in the manufacture of an optical filter.
  • Said optical filter may have preferential absorption at certain wavelengths.
  • the wavelengths of said preferential absorption of said optical filter may be altered by means of altering the concentration of nanoparticles in the ink.
  • the wavelengths of said preferential absorption of said optical filter may be altered by means of altering the distribution of sizes of nanoparticles in the ink.
  • the wavelengths of said preferential absorption of said optical filter may be altered by means of altering the distribution of shapes of nanoparticles in the ink.
  • the ink may be used to modify the absorption of radiation, especially of solar radiation, by a photovoltaic cell.
  • the ink may be used to modify the photocurrent generated by a photovoltaic cell under conditions of radiation intensity on the cell.
  • the ink may be used to induce or enhance a plasmonic response.
  • Fig. 1 is an example of a microfluidic flow chemistry synthesis for the first step (silver seed synthesis) of the process for the production of discrete high definition silver nanoparticles;
  • Fig. 2 is an example of a microfluidic flow chemistry synthesis for the second step (silver seed growth into silver nanoparticles) of the process for the production of discrete high definition silver nanoparticles;
  • FIG. 3(A) is a schematic of a microfluidic system using a generic microfluidics chip for silver seed production;
  • (B) is a detailed schematic of the generic microfluidics chip for silver seed production;
  • Fig. 4 is an example of implementation of protocol for silver seed production using a microfluidic chip system
  • Fig. 5 is a schematic showing a microfluidic chip set up showing reagent input sequencing for general nanoparticle production
  • Fig. 6 is a schematic of a microfluidics chip set up showing reagent output sequencing specifically designed for discrete high definition silver nanoparticle synthesis;
  • Fig. 7 illustrates information on microfluidics chip design requirements showing stream input and mixing criteria;
  • Fig. 8 shows discrete silver nanoparticles produced using seeds synthesized using a generic microfluidic chip system with a flow rate ratio of 8:1 for solution 1 and 2.
  • Fig. 9 shows discrete silver nanoparticles produced using seeds synthesized using a generic microfluidic chip system with a flow rate ratio of 8:1 for solution 1 and 2. Conventional wet chemistry was used to grow the seeds to form the nanoparticles;
  • A) is a UV-visible spectrum;
  • B) is a TEM micrograph;
  • C) is a plot showing the size distribution of the nanoparticles;
  • D is a plot showing the distribution of hexagons and triangles/truncated triangles;
  • Fig. 10 is a UV -Visible spectrum of silver seeds produced with a flow rate ratio of 8:1 of solution 1 and 2 respectively;
  • Fig. 11 shows the dependence of seed parameters with variation of flow rate solution 1 (AgNO 3 and TSC) from 3 to lOml/min while keeping flow rate of solution 2 constant at lml/min;
  • A is a plot showing FWHM dependence;
  • B is a plot showing the dependence of the maximum wavelength;
  • Fig. 12 (A) is a graph showing the UV-visible spectrum for nanoparticles; and (B) is a TEM micrograph of the nanoparticles, the discrete silver nanoparticles were produced from seeds synthesised by conventional wet chemistry (step (a)) and the seeds were grown into nanoparticles using a microfluidics processor (step (b));
  • Fig. 13(A) is a UV-Visible spectra for silver seeds synthesised in presence of PSSS using a microfluidics processor method (seeds); discrete silver nanoparticles prepared by a conventional wet chemistry growth in presence of PSSS (step (b)) of microfluidics synthesised silver seeds (step (a)) (beaker experiment); and discrete silver nanoparticles produced from niicrofluidics synthesised silver seeds (step (a)) and microfluidics grown nanoparticles (step (b)) (microfluidics reaction technology);
  • (B) is a UV- Visible spectra of a silver seed solution synthesised using a conventional wet chemistry method (seeds); discrete silver nanoparticles prepared using a conventional wet chemistry method for both steps (a) and (b) (beaker experiment); and discrete silver nanoparticles prepared using a microfluidics process and the conventionally prepared seeds (step (b
  • Fig. 14 is a UV- Visible spectra for a range batches of discrete silver nanoparticles prepared under the same conditions by conventional wet chemistry method for both steps
  • Fig. 15 (A), (B) and (C) are TEM images for a range of discrete silver nanoparticles prepared under the same conditions by conventional wet chemistry method for both steps 1 and 2;
  • Fig. 16 is a UV- Visible spectra for a range of batches of silver seeds (Step 1) prepared under the same conditions by conventional wet chemistry method (each line represents a different batch);
  • Fig. 17 are transmission electron microscope (TEM) images of silver nanoparticles used in an embodiment in the invention.
  • Fig. 18 is a histogram of silver nanoparticle diameter distribution in the ink after removal of the polymer in accordance with an embodiment of the invention.
  • FIG. 19 (A) and (B) are TEM images of nanoparticles self assembling to form linear paths in accordance with an embodiment of the invention
  • Fig. 20 are TEM images showing the formation of a conductive track structure from the ink by two processes in accordance with an embodiment of the invention: (A) by the merging of nanoparticles and (B) by the assembly of nanoparticles;
  • Fig. 21 (A) to (C) are TEM images showing the formation of dendrites and fractals using an ink in accordance with an embodiment of the invention;
  • Fig. 22 is a graph of the viscosity of PVA-based Nanosilver inks as a function of PVA concentration
  • Fig. 23 is an illustration of a silver nanoparticle thin film with thickness measurement using razor blade techniques
  • Fig. 24 (A) is a UV visible spectrum and (B) is a TEM micrograph of ink incorporating silver nanoplates with one predominant shape in aqueous solution;
  • Fig. 25 (A) is a UV visible spectrum and (B) is a TEM micrograph of ink incorporating silver nanoparticles with two dominant shapes in aqueous solution made by a batch wet chemistry method;
  • Fig. 26 (A) is a UV visible spectrum, (B) is a TEM micrograph of ink incorporating silver nanoplates made using a microfluidic process for synthesising the seeds and a batch wet chemistry method for growing the seeds, (C) is the distribution of two dominant shapes in aqueous solution, (D) is an AFM measurement of the height of such a nanoparticle;
  • Fig. 27 is a UV visible spectrum of silver nanoplates with two dominant shapes in a range of organic solvents
  • Fig. 28 is a TEM image of a sample of concentrated silver nanoplate ink
  • Fig. 29 (A) and (B) are TEM micrographs of triangular shaped and hexagonal shaped nanoplates respectively;
  • Fig. 30 (A) is an image of ink-jet printed silver nanoplate ink line before annealing; and (B) is an image of ink-jet printed silver nanoplate ink line after annealing at 200 0 C for 6 min;
  • Fig. 31 are AFM images showing a A) 10x10 ⁇ m 2 and B) 3x3 ⁇ m 2 top view of the silver nanoplate ink printed line of Fig. 30;
  • Fig. 32 A) is an AFM image and B) is an analysis of a cross section of the silver nanoplate ink printed line of Fig. 30 showing a 96 run line thickness;
  • Fig. 33 are schematic illustrations of conductive paths in nanoparticles illustrates that (A) spherical particles have only single point contact whereas shaped nanoparticles (nanoplates) such as hexagons (B), triangles (C) a shaped mixtures (D) provide increased conductive pathways;
  • Fig. 34 is a metallurgical microscope image of the printed silver nanoplate ink on a DK test chip with gold metallisation and silicon nitride passivation. The arrows indicate the clearly visible two probe marks which were used for the ink electrical characterisation;
  • Fig. 35 is a UV visible spectra demonstrating that the surface plasmonics / light trapping / wave guiding properties of the inks described herein can be tuned across the relevant sun spectral range;
  • Fig. 36 A to C are schematics of: photovoltaic devices incorporating nanoplates as (A) an active material; (B) a semi-transparent top electrode; and (C) a bottom electrode; and
  • Fig. 37 is a UV-visible absorption spectra and images of optical filter thin films deposited on glass substrates using shaped silver nanoplate ink solutions of various colours.
  • Nanoplates are a subset of nanoparticles having lateral dimensions (such as edge length) that are larger than their height (thickness).
  • the term nanoplate includes for example nanodisks and nanoprisms. Nanoprisms have an equilateral triangular shape.
  • the nanoplates are high definition silver nanoplates and are synthesized or produced using a two step process: First silver seed solution is produced (step (a)) from a silver source and in a second step (step (b)) these silver seeds are used to grow the silver nanoplates in the presence of a silver source.
  • the silver source may be a silver salt or a complexed silver compound or salt.
  • the nanoplates may be synthesized using batch wet chemistry, microfluidic processing shear mixing, or a combination of these methods.
  • Nanoparticles can be prepared according to the seed mediated methods described in
  • Microfluidics technologies for the production of the discrete high definition silver nanoparticles can be applied to the silver seed production step (step (a)), or the growth of the seed to step (step (a).
  • Microfluidic methods for the production of discrete high definition silver nanoparticles allows for silver nanoparticles to be produced in a predetermined and controlled manner.
  • the silver nanoparticles formed are highly shaped, e.g. contain a high percentage of triangles and hexagons compared to spheres, and have a narrow size distribution in a desired size range such as 25nm or 30nm or 40nm or larger or smaller.
  • Such nanoparticles will have a UV-visible spectrum with a main peak at wavelengths longer that 420nm and the FHWM of this peak will be less than lOOnm.
  • step (a) and step (b) enables scaled-up production of discrete high definition silver nanoparticles with high batch to batch reproducibility and improved nanoparticle properties including narrower size distribution, increased presence of shaped nanoparticles and a higher uniformity of the silver nanoparticles.
  • the microfluidic methods provide a control over the size, shape, spectral profile and surface chemistries of discrete high definition silver nanoparticles. This technology can be adapted for the scaled up production of a range of both metallic and non metallic high quality nanoparticles.
  • nanoparticles having a controlled shape and size can be produced by mixing the reagents in small volumes such as between about 10 picoliters (pi) to about lOO ⁇ l. Microfluidic methods are ideal for the thorough and rapid mixing of reagents in such small volumes.
  • reagents may be performed in small volumes in a microfluidic reactor at high or differential flow rates. For example at flow rates between about 1 ml/min to about 10ml/min for low pressure systems and flow rates of at least lOml/min up to litres/min for high pressure systems.
  • the reagents used in step (a) and/or step (b) of the process may have differential flow rates.
  • the flow rate of individual reagents can be variably controlled within a microfluidic reaction system resulting in the reagent solutions being rapidly and thoroughly mixed.
  • the ratio of the reagents, and/or the ratio at which the reagents are mixed can impact the physical properties of the nanoparticles formed. For example, an excess of about eight times the reducing agent solution to the silver salt solution has been found to be optimum for the reaction chemistry for producing silver seeds in step (a) of the process.
  • step (b) of the process may require a microfluidic reactor which is capable of delivering reagent solutions under high pressures for example between about 35 MPa to about 275 MPa (about 5000 psi to about 40000 psi), such as about 140 MPa (about 20000 psi).
  • a microfluidic reactor which is capable of delivering reagent solutions under high pressures for example between about 35 MPa to about 275 MPa (about 5000 psi to about 40000 psi), such as about 140 MPa (about 20000 psi).
  • Mixing reagents under pressure in step (a) and/or step (b) of the process may assist with the rapid and thorough mixing of the reagents.
  • the use of high pressure flow and/or variable differential flow rates of reagents may allow for a uniform reaction to take place.
  • the pressure and flow rate of reagents and the dimensions of the microfluidic reactor may be such that a turbulent flow of reagents is generated at the point at which the reaction takes place. Turbulent flow of reagents may thereby promote thorough mixing of the reagents and maintain consistent control of the reaction chemistry in a continuous microfluidic flow process.
  • the microfluidic reactor allows for the continuous flow and through mixing of reagents under controlled conditions thereby allowing a true scaling up of the reaction chemistry without compromising the quality of the nanoparticles produced.
  • the thorough and rapid mixing of reagents allows for certain desired characteristics of the silver nanoparticles to be controlled and reproducibly produced. Such controlled reproducibility is not always possible in a conventional wet batch chemistry reaction in which reagents are mixed in higher volumes compared to the microfluidic process resulting in variations in nanoparticle characteristics both within a batch, and between batches.
  • Steps (a) and (b) can be combined in some embodiments of the invention to produce a single step microfluidic production method for these nanoparticles.
  • the order of addition of the reagents, the type of reagents used, the concentration of the reagents can all be varied. Additional reagents can be introduced into the production steps.
  • the microfluidics method allows for variations in the process parameters, these variations can be used to controllably tune various physical properties and attributes of the nanoparticles, such as their size, shape, thickness and optical spectrum.
  • microfluidic methods enable the reproducible production of high definition silver nanoparticles with predetermined, size, shape, narrow distribution of size and shape.
  • a microfluidics processor method can be used to produce discrete high definition silver nanoparticles in large volume batches.
  • pressure and shear rate parameters silver nanoparticles can be produced on an industrial scale while retaining control of the reaction chemistry conditions necessary to produce controlled size and shape range silver nanoparticles.
  • a high pressure for example in the range of about 35 MPa to about 275 MPa, such as about 140 MPa
  • high shear rate for example between about 1 x 10 6 s "1 to about 50 x 10 6 s "1 , typically about 10 7 s "1
  • microfluidics processor method to produce silver nanoparticles in 500 ml batches.
  • the process is capable of producing several liters per hour at flow rates typically in the range of about 10 ml/minute to about 500 ml/minute, while a wet chemistry method is limited to 100ml batch production.
  • Nanoparticles can also be prepared by a shear mixing process comprising the steps of: (a) forming silver seeds from an aqueous solution comprising a reducing agent, a stabiliser, a water soluble polymer and a silver source; and
  • step (a) and/or step (b) are performed at a shear flow rate between about 1x10 1 s "1 and about 9.9XlO 5 S "1 .
  • Example 1 microfluidic production of silver seeds (step (a))
  • step (a) We have found that by using microfluidics technologies for the production of silver seeds control over the synthesis of the silver seeds is the most important factor in producing discrete high definition silver nanoparticles with predetermined, size, shape and a narrow distribution of size and shape.
  • Fig. 1 is a schematic illustrating the set up for microfluidic synthesis of silver seeds.
  • step (b)) of producing silver nanoparticles by growing silver seeds was in this case performed using conventional batch chemistry.
  • the constituent chemicals and products may vary from those detailed in Fig. 1 wherein product 1 is a silver nitrate (AgNO 3 ) and Trisodium Citrate (TSC) solution and product 2 is a silver seed solution.
  • a silver source in this case silver nitrate
  • TSC Trisodium Citrate
  • a silver source in this case silver nitrate
  • trisodium citrate at 0°C.
  • sodium borohydride (NaBH 4 ) is added to the AgNO 3 -TSC solution and the mixture is incubated at O 0 C. Specific details are outlined in Example 2 below.
  • the microfluidics set-up for the production of the silver seeds is as shown in Fig. 3.
  • This consists of a microfluidic reactor chip system (micromixer glass or polymer chips) to which the component solutions, such as those described in Fig. 1 are added at a controlled rate using pumps.
  • the microfluidics chip may be of a generic type, i.e. an "off the shelf chip that has not been specifically customized for the production of silver seeds or the growth of silver seeds to produce discrete high definition silver nanoparticles. Details of a suitable generic chip are given in Fig. 3 B and in Table 1 below. Altematively, the microfluidic chip may be custom designed for the production of silver seeds and/or the growth of silver seeds into nanoparticles. Referring to Fig. 7, a suitable chip is shown.
  • product 1 is a sodium borohydride (NaBH 4 ) and Trisodium Citrate (TSC) solution and product 2 is a silver nitrate (AgNO 3 ) solution.
  • the microfluidics set-up for the production of the silver seeds is as shown in Fig. 3 A, this consists of a microfluidic reactor chip system (micromixer glass or polymer chips) to which the component solutions, such as those described in Fig. 1 are added at a controlled rate using pumps.
  • the microfluidics chip may be of a generic type, i.e. an "off the shelf chip, or a custom designed chip.
  • a polymer such as poly(sodiumstyrene sulfonate) (PSSS) may be added to step (a).
  • PSSS poly(sodiumstyrene sulfonate)
  • PSSS could be included in one or more of the silver nitrate solution, trisodium citrate solution, and sodium borohydride solution at a concentration of about 10 ⁇ 4 M.
  • This method has enabled unprecedented reproducibility of the production of high definition of silver nanoparticles with predetermined, size, shape, narrow distribution of size and shape.
  • Example 2 - protocol for the production of silver seeds step (a using a microfluidic chip system Referring to Figs 3 A and 4, dissolve 37.8 mg of sodium borohydride in 100 ml of water (Solution 1 of Fig 3A). Dissolve 5 mg of silver nitrate and 7.4 mg of trisodium citrate in 100 ml of iced cooled water in an ice bath (solution 2 of Fig. 3A).
  • Set pump 1 and pump 2 flow rates for example at 1 ml/min and 8 ml/min respectively;
  • FIG.5 A more generic setup for reagent input sequencing for general nanoparticle production is depicted in Fig.5. This can be applied to the production method for of a wide range of nanoparticles including the methods of producing high definition silver nanoparticles.
  • setup conditions and reagents would need to be altered for each particular type of nanoparticle to be produced.
  • step ( a) Results of experiments using a generic microfluidic chip system for the production of silver seeds (step (a)) are given below.
  • step (b)) the growth of these seeds to produce discrete high definition silver nanoparticles is carried out using the conventional batch chemistry method.
  • silver seeds were synthesised using a generic microfluidic chip system according to the following method:
  • Pump 1 was run for 30 s and the by-product collected. With pump 1 still running, pump 2 was run for 30 s and the by-product collected. Prior to stopping the pumps, 5 ml of final seed product was then collected while pumps 1 and 2 were still running.
  • silver seeds were grown into nanoparticles (step (b)) using the conventional wet chemistry method below.
  • Fig. 8 shows the UV-visible spectrum and TEM image of discrete high definition silver nanoparticles produced using seeds produced by the generic microfluidic chip with a flow rate ratio of 8:1 for solution 1 and 2.
  • the average nanoparticle size is 21.6 ⁇ 7.5 nm, with 75.4% of the nanoparticles being shaped, for example, triangular, truncated triangular and hexagonal.
  • the FWHM of the main UV-visible spectral peak is 105nm.
  • the peak maximum wavelength is in the region of 520nm.
  • Fig. 9 shows the UV-visible spectrum and TEM image of discrete high definition silver nanoparticles produced using seeds produced by the generic microfluidic chip with a flow rate ratio of 8:1 for solution 1 and 2.
  • the average nanoparticle size is 24.0 ⁇ 8.9 nm, with 44.9% of the nanoparticles being shaped, for example, triangular, truncated triangular and hexagonal.
  • the FWHM of the main UV-visible spectral peak is 120nm.
  • the peak maximum wavelength is in the region of 519nm.
  • the nanoparticles of Figs. 8 and 9 demonstrate the ready reproducibility of discrete high definition silver nanoparticles with similar size, narrow size distribution and a high percentage of shaped nanoparticles, using a microfluidic method to produce the silver seed nanoparticles.
  • Fig. 10 Shows UV-visible spectra of microfluidic seeds produced using the generic microfluidic chip with a flow rate ratio of solution 1 and 2 of 8: 1.
  • Fig. 11 shows the dependence of seed FWHM and maximum wavelength with variation of flow rate of solution 1 (AgNO 3 and TSC) from 3 to 10 ml/min while keeping flow rate of solution 2 constant at 1 ml/min.
  • Example 4 microfluidic growth of silver seeds (step b)
  • microfluidics processor method Due to blocking and clogging difficulties when using microfluidic chip systems for carrying out step (b), the growth of silver seeds to form discrete high definition silver nanoparticles a microfluidics processor method was selected for this step.
  • a limited number of commercial microfluidics processors are available. The one selected is from a company Microfluidics located at 30 Ossipee Road, P.O. Box 9101 Newton, MA 02464-9101, U.S.A.
  • This microfluidics processor operates at very high pressures of the order of 20,000 psi and provides high shear rates maximizing the energy-per unit fluid volume.
  • Product 3 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) solution
  • Product 4 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) and silver seed solution
  • Product 5 is a solution of the discrete high definition silver nanoparticles
  • a microfluidics processor to carry out step (b), the growth of silver seeds to produce high quality discrete high definition silver nanoparticles.
  • the silver seeds were synthesised using a conventional wet chemistry method.
  • the Microfluidics International Corporation microfluidics processor technology was used to create a 500 ml batch of discrete high definition silver nanoparticle solution.
  • the average nanoparticle size was about 37 ⁇ 18 run, with about 31% of the nanoparticles being shaped, for example, triangular, truncated triangular and hexagonal.
  • the FWHM of the main UV-visible spectral peak was about 98 run.
  • step (b) Blocking and clogging difficulties were encountered in some experiments when a microfluidic chip systems was used for carrying out step (b), the growth of discrete high definition silver nanoparticles from silver seeds. It was found that blocking and clogging of the microfluidic system could be overcome if the reagents were under pressure for this step.
  • a microfluidics system supplied by a company now known as Microfluidics International Corporation located at 30 Ossipee Road, P.O. Box 9101 Newton, MA 02464-9101, U.S.A.
  • This microfluidics processor operates at very high pressures of the order of about 140MPa (about 20,000 psi) and provides high shear rates in the range of about 1 x 10 6 s “1 to about 50 x 10 6 s "1 , thereby maximizing the energy-per unit fluid volume.
  • the microfluidics processor used allowed the reagent streams to be pressurized so that the reagent streams traveled at high velocities to meet in a reaction chamber where turbulent mixing took place.
  • the microfluidics processor also allowed for continuous flow of the reaction product (silver nanoparticles). Details of typical processor operating parameters are given in Table 2 below.
  • Fig. 2 shows a microfluidic system set up for growing nanoparticles from silver seeds.
  • constituent chemicals and products may vary, in this Example product 3 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) solution, product 4 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) and silver seed solution, and product 5 is a solution of the discrete high definition silver nanoparticles.
  • product 3 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) solution
  • product 4 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) and silver seed solution
  • product 5 is a solution of the discrete high definition silver nanoparticles.
  • FIG. 12B A TEM image of the silver nanoparticles produced (product 5) is shown in Fig. 12B.
  • Example 5 Experimental Results for Application of micro fluidics methods to silver seed growth (step (b))for the production of discrete silver nanoparticles
  • step (b) The objective was using the microfluidics processor to carry out step (b), the growth of silver seeds, which were produced using a conventional wet chemistry method, to produce high quality discrete high definition silver nanoparticles.
  • Example 4 We used Microfluidics Inc microfluidics processor technology described in Example 4 above to create a 500 ml batch of discrete high definition silver nanoparticle solution.
  • the average nanoparticle size is 37 ⁇ 18 nm, with 31% of the nanoparticles being shaped, for example, triangular, truncated triangular and hexagonal.
  • the FWHM of the main UV-visible spectral peak is 98 nm.
  • microfluidics processor method can be used to produce discrete high definition silver nanoparticles in large volume batches.
  • the silver nanoparticles can be produced on an industrial scale.
  • a microfluidics processor method to produce 500 ml batches in a few minutes only. The process is capable of producing several liters per hour, while the wet chemistry method is limited to 100ml production.
  • Example 6 Application of microfluidics methods to both silver seed production (step a) and silver seed growth (step (b)) for the production of discrete silver nanoparticles
  • the Microfluidics International Corporation microfluidics processor technology described in Example 4 was also applied to the production of silver seeds (step (a)) and in a further stage these microfluidic processor produced seeds were grown to produce discrete silver nanoparticles (step (b)) also using a microfluidics processor.
  • microfluidics methods to carry out the complete process for producing discrete high definition silver nanoparticle i.e. both steps (a) and (b).
  • Fig. 6 a generic set up for reagent input sequencing for the synthesis of high definition nanoparticles is shown.
  • Step fa) synthesising silver seeds
  • a solution comprising 2.94 ⁇ lO '4 M AgNO 3 and 2.5 ⁇ lO "4 M TSC and 10 "4 M PSSS in water was made and poured into the reservoir of a microfluidics processor.
  • a 0.01 M solution Of NaBH 4 was introduced into the microfluidics processor.
  • the NaBH 4 and AgNO 3 - TSC solutions were mixed at flow rates of 15ml/min and 485ml/min respectively with a continuously flowing stream of the AgNO 3 - TSC solution and the material was processed for one pass at 140MPa (20,000psi).
  • Step (b) growing silver nanoparticles
  • the PVA - AgNO 3 - PSSS-silver seed solution was placed in the reservoir of a microfluidics processor.
  • a 0.0 IM solution of ascorbic acid solution was introduced to a 475ml/min continuously flowing stream of PVA - AgNO 3 - PSSS-silver seed solution at a rate of 25ml/min.
  • the material was processed for 1 pass at 35 MPa (20,000psi).
  • Fig. 13 A The UV-visible spectrum of silver seeds produced using a microfluidics processor (processed seeds) and the discrete high definition silver nanoparticles produced by the subsequent growth of these microfluidics processor produced silver seeds also using a microfluidics processor (microfluidics reaction technology) are shown in Fig. 13 A. Also shown are discrete silver nanoparticles produced by the conventional wet chemistry growth of the microfluidic processor synthesized silver seeds (beaker experiment). It is clear from the spectra shown in Fig. 13A that the microfluidic process of growing the microfluidic synthesized silver seeds (i.e.
  • step (a) and (b)) results in the production of discrete silver nanoparticles with a much higher presence of shaped silver nanoparticles compared to a conventional wet chemistry operation of the growth step as is signified by the much more distinct peak in the region of 345 nm in the case of the micro fluidics processor produced discrete silver nanoparticles and a much larger shoulder plasmon band in the 450nm region.
  • a silver seed solution was synthesised using a conventional wet chemistry method (seeds) and discrete silver nanoparticles were prepared by either using a conventional wet chemistry method for growing the wet chemistry synthesised silver seeds (beaker experiment) or a microfluidic processor for growing conventionally synthesized silver seeds. It is clear again from the spectra shown in Fig. 13B that using a microfluidics process for step (b) results in the production of discrete silver nanoparticles with a high presence of shaped silver nanoparticles compared to a conventional wet chemistry method.
  • Example 7 (Comparative Example) - Wet Chemistry Batch Nanoparticle Production both step (a) and step (b)
  • a wet chemistry method was used to synthesize silver seeds (step (a)) and growing the silver seeds to form discrete silver nanoparticles (step (b)), as described in WO04/086044. Briefly, silver seeds were formed by vigorously stirring an aqueous mixture of silver nitrate, trisodium citrate and sodium borohydride. The typical ratio of silver nitrate : trisodium citrate was about 1 : 1 and the typical ratio of silver nitrate : sodium borohydride was about 1 : 8.
  • the batch wet chemistry method restricts the production volume generally to the order of 50ml, with a maximum of up to 100ml of discrete silver nanoparticles being produced in any one batch.
  • Batch to batch reproducibility difficulties are experienced, as indicated by the diverse range of UV-Visible spectra of discrete silver nanoparticles using wet chemistry prepared under precisely the same conditions as shown in Fig.14.
  • These batches of discrete silver nanoparticles have spectra, whose maximum peak wave lengths range between 400nm and 700nm, have FWHM in excess of 150nm and have spectra which vary between single peaked to twin peaked where both spherical and shaped associated peaks are of similar intensity to the case where the shaped associated peak is dominant.
  • FIG. 15 shows representative TEM images of discrete silver nanoparticles prepared using wet chemistry in steps (a) and (b) (wide size distribution (Fig. 15 A and B) and low presence of shaped nanoparticles (Fig. 15 C).
  • Fig. 15 A and B wide size distribution
  • Fig. 15 C low presence of shaped nanoparticles
  • Fig. 16 shows UV-visible spectra for three different batches of silver seeds produced under the same conditions using conventional wet chemistry.
  • the spectra profiles are very similar with a peak maximum wavelength in the region of 399 nm and a FWHM of the order of 65 nm.
  • These silver seeds are typical of those used in the wet chemistry step (b) resulting in discrete silver nanoparticles which have the range of variation and poor reproducibility shown in Figs. 14 and 15.
  • the UV-visible spectra of wet chemistry (Fig. 16) and microfluidic (Fig. 10) produced silver seeds appear to be comparable.
  • microfluidics methods for the production of silver seeds is key in achieving discrete silver nanoparticles with the required characteristics, controlled size, narrow size distribution, high presence of shaped nanoparticles and good batch to batch reproducibility.
  • microfluidics methods such as microfluidics processors, can be readily applied to produce litres per hour of the discrete silver nanoparticles with out sacrificing quality.
  • Example 8 Process for selectively producing nanoplates
  • the process for synthesizing nanoparticles may be tailored for the selective production of nanoplates, in particular the synthesis process may be tailored for the selective production of triangular silver nanoplates.
  • the following methods result in the production of triangular silver nanoplates as the dominant nanostructure.
  • Triangular Silver Nanoplates can be prepared according to the seed mediated methods described in PCT/IE2008/000097, the entire contents of which is incorporated herein by reference.
  • TSNP were prepared as follows: 5 ml of 2.5 mM trisodium citrate, 250 ⁇ L of 500 mg.L "1 1,000 kDa poly(sodium styrenesulphonate) (PSSS) and 300 ⁇ L of freshly prepared 10 mM NaBH 4 were combined followed by addition of 5 mL of 0.5 mM AgNO 3 at a rate of 2 ml.min "1 while stirring vigourously.
  • the triangular silver nanoplates were grown by combining 5 mL distilled water, 75 ⁇ l of 10 mM freshly prepared ascorbic acid and various quantities of seed solution followed by addition of 3 mL of 0.5 mM AgNO 3 at a rate of 1 ml.min "1 . followeded by the addition of 0.5 ml of 25mM Trisodium citrate.
  • the size of the TSNP can be controlled by adjusting the volume of seeds used in the growth step.
  • Microfluidics TSNP can be prepared according to the seed mediated microfluidics methods described in PCT/IE2008/000097, the entire contents of which is incorporated herein by reference.
  • microfluidic synthesis of TSNP comprises the steps of:
  • a mixture of 3 niL of 10 mM sodium borohydride, 2.5 mL of 500 mgL "1 poly(sodiumstyrene sulfonate) and 100 mL of 2.5 x 10 "3 M trisodium citrate in water (solution 1) was prepared and connected to pump 1.
  • a solution comprising 100ml of 5 x 10 "4 M silver nitrate (solution 2) was prepared and connected to pump 2.
  • the flow rates of pump 1 and pump 2 were set for example at 1 ml/min and 1 ml/min respectively.
  • the pump lines were primed with the solution to be used in them and pump 1 and pump 2 were run in succession for ⁇ 2min each such that an initial volume of ⁇ 2mL of each solution was run through the microfluidic chip and discarded. Pump 1 and pump 2 were run together and the first ImI of the product solution was discarded. The subsequent 5 ml of seed product was collected and both the pumps were stopped.
  • the size of the TSNP can be controlled by adjusting the volume of seeds used in the growth step (step (b)).
  • Step (a) and/or step (b) may be carried out using a high pressure microfluidics process which would enable the production of large volumes of TSNP.
  • Shear mixing In an exemplary example, silver seeds were produced in a shear mixer having the following parameters: Speed 16,000 rpm Gap size 0.15 mm, Radius of outer gap 15.05 mm, 15 cuttings/360 0 Shear rate 1.68 x 10 5 s "1 ; Shear frequency 3.36 Mio. Min "1 .
  • a suitable shear mixer is sold by IKA process under item Magic Lab UTL 6F.
  • H 2 O 90 mL
  • TSC 10 mL, 25 mM
  • NaBH 4 6 mL, 10 mM
  • PSSS 5 mL, 0.5 mg/niL
  • This solution was then transferred into the mixing chamber of a shear mixer.
  • the motor was switched on at a tip speed of 23 m/s and the solution was allowed to circulate for about 2 minutes.
  • AgNO 3 (10O mL, 0.5 mM) was then introduced through an adapted inlet at a rate of 40 ml/min using a peristaltic pump. After the AgNO 3 addition was complete, the solution was allowed to circulate for approximately 5 min before being tapped off.
  • the cooling system was switched on so that the growth was carried out at about 25°C - 3O 0 C.
  • the seeds were allowed to age for Ih before further use.
  • silver nanoplates were produced in a shear mixer having the following parameters: Speed 16,000 rpm Gap size 0.15 mm, Radius of outer gap 15.05 mm, 15 cuttings/360 0 Shear rate 1.68 x 10 5 s "1 ; Shear frequency 3.36 Mio. Min "1 .
  • a suitable shear mixer is sold by IKA process under item Magic Lab UTL 6F.
  • a IL scale production of silver nanoplates at a concentration of 17 ppm were grown from silver seeds as follows:
  • H 2 O 500 mL
  • seeds (30 mL) and ascorbic acid 7.5 mL, 10 mM
  • This solution was then circulated at a shear rate of 1.68 x 10 5 s "1 for about 2 min and AgNO 3 (300 mL, 0.5mM) was added at a rate of 100 mL/min using a peristaltic pump.
  • TSC 200 mL, 25 mM was added using the peristaltic pump and the sol was allowed to recirculate for a further 2 minutes before being tapped off.
  • the reagent volumes and concentrations and process parameters may be modified.
  • the size of the TSNP can be controlled by adjusting the volume of seeds used in the growth step.
  • the solutions may be mixed at a shear flow rate between about IxIO 1 s "1 and about 9.9xlO 5 s "1 .
  • Example 9 Properties of triangular silver nanoprisms
  • the silver nanoprisms produced in accordance with the methodologies of Example 8 are monodisperse (discrete), well-defined silver nanoprisms of varying edge length.
  • the triangular silver nanoplates have an aspect ratio from about 2 to about 25 with increasing edge length wherein aspect ratio is the ratio of the edge length and thickness of a nanoplate and is calculated using equation 1 below.
  • Aspect ratio is the ratio of the length and thickness of nanoplate and is calculated using equation
  • Nanoplates having a high aspect ratio means that larger nanoplates retain many of the optical and electronic properties normally only associated with smaller nanoparticles.
  • Example 10 Production of an ink
  • the process for making the ink comprises the steps of :
  • steps (a) and (b) may be performed in accordance with any of methodologies outlined in Examples 1 to 8 above and once the nanoparticles have been produced, step (c) can be performed.
  • steps (a) and (b) were performed using microfluidic processing as follows.
  • Step (a) - microfluidic production of silver seeds step a
  • Fig. 1 is a schematic illustrating the set up for microfluidic synthesis of silver seeds.
  • Protocol for the production of silver seeds using a microfluidic chip system Dissolve 37.8 mg of sodium borohydride in 100 ml of water ("Solution 1").
  • solution 2 Dissolve 5 mg of silver nitrate and 7.4 mg of trisodium citrate in 100 ml of iced cooled water in an ice bath ("solution 2"). Connect solution 1 and solution 2 to pump 1 and pump 2 respectively of a microfluidic reactor
  • Set pump 1 and pump 2 flow rates for example at 1 ml/min and 8 ml/min respectively;
  • Fig. 2 is a schematic illustrating the set up for microfluidic synthesis of silver nanoparticle ink.
  • a commercial microfiuidics processor (such as that supplied by Microfluidics, Inc., 30 Ossipee Road, P.O. Box 9101 Newton, MA 02464-9101, U.S.A.) operated at very high pressures of the order of 20,000 psi and providing high shear rates maximizing the energy-per unit fluid volume, was used to make the ink from the seed solution.
  • Product 3 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) solution
  • Product 4 is a silver nitrate (AgNO 3 ) polyvinyl alcohol (PVA) and silver seed solution
  • Product 5 is a solution of the discrete high definition silver nanoparticles
  • This methodology can be applied to the production of a wide range of nanoparticles including the methods of producing high definition silver nanoparticles.
  • the setup, setup conditions and reagents would need to be altered for each particular type of nanoparticle to be produced.
  • the constituent chemicals and products may vary from those detailed in Fig. 1 wherein product 1 is a silver nitrate (AgNO 3 ) and Trisodium Citrate (TSC) solution and product 2 is a silver seed solution.
  • a silver source in this case silver nitrate
  • TSC Trisodium Citrate
  • the microfluidics set-up for the production of the silver seeds consists of a microfluidic reactor chip system (micromixer glass or polymer chips) to which the component solutions, such as those described in Fig. 1 are added at a controlled rate using pumps.
  • the microfluidics chip may be of a generic type, i.e. an "off the shelf chip that has not been specifically customized for the production of silver seeds or the growth of silver seeds to produce discrete high definition silver nanoparticles. Details of a suitable generic microfluidic chip are given in Table 3 below.
  • This method has enabled unprecedented reproducibility of the production of high definition of silver nanoparticles with predetermined, size, shape, narrow distribution of size and shape.
  • nanoparticle ink may be performed by optionally concentrating the nanoparticles, for example by means of centrifugation, and by the addition of chemical, biological or polymer species, for example, polyethylene oxide.
  • a Microfluidics Inc microfluidics processor technology as described above was used to create a 500 ml batch of discrete high definition silver nanoparticle solution.
  • the average nanoparticle size is 37 ⁇ 18 nm, with 31% of the nanoparticles being shaped, for example, triangular, truncated triangular and hexagonal.
  • the microfluidics processor method can be used to produce discrete high definition silver nanoparticles in large volume batches.
  • the silver nanoparticles can be produced on an industrial scale.
  • Example 12 Production of various formulations of nanoparticle inks
  • a microfluidics processor technology as described above was used to create seven batches of discrete high definition silver nanoparticle solutions of varied formulation, as described in Table 4.
  • the ink may comprise a solution or suspension or mixture of nanoparticles in a liquid wherein said nanoparticles have a distribution of geometric shapes within which either two or more shape geometries, or in preferred embodiments of the invention one shape geometry, selected from one of the following list, are/is predominant: a. spherical; b. ellipsoidal; c. circular plate shaped; d. elliptical plate shaped; e. tetragonal; f. triangular; g. hexagonal; h. tetragonal plate; i. triangular plate; j. hexagonal plate; k. cubic;
  • the ink comprises silver nanoplates with one shape geometry, selected from the following is predominant:
  • the inks are electrically conducting inks and may be used to form electrically conducting structures.
  • the inks are thermally conducting and can be used to generate thermally conducting paths.
  • the methods to generate nanoparticles described herein allow for the control of the range of sizes and/or shapes of particles as defined by one or more of their principal dimensions (height, length and width.)
  • the ability to control of size and shape of nanoparticles can be exploited to produce inks having specific properties for example, by adjusting the concentration of the nanoparticles in the ink may provide for an ink that when printed will have an electrically conductive path, while minimising the metal nanoparticle content of the ink.
  • the inks described herein allow for narrow conductive paths or lines or wires or structures to be made or printed.
  • the width of a conductive path can be reduced to a dimension comparable to the size of the nanoparticles. It is feasible that conductive paths with a width of less than 100 nm may be fabricated from the inks described herein.
  • chemical or biological substances may be added to the ink to promote the aggregation or self-assembly of the nanoparticles to make conductive paths.
  • the ink may be allowed to form a conductive path without additional chemical or biological agent treatment after deposition.
  • the ink may be deposited on a structured surface, such as a polymer, in which the surface structure assists the formation of conductive paths from the ink.
  • the invention further provides for the formulation of an ink comprising metal nanoparticles at a concentration consistent with a low probability of the formation of a conductive path.
  • an ink comprising metal nanoparticles at a concentration consistent with a low probability of the formation of a conductive path.
  • metal nanoparticles present on a material, but deposited in such a way that they do not make a conductive path. It is possible to form an ink containing metal nanoparticles that is not conductive because the nanoparticles are discrete, and because their size and shape may be controlled within sufficiently narrow ranges.
  • inks described herein may be used in a wide variety of applications described below.
  • the images in Figure 17 illustrate an example of the characteristics of the silver nanoparticle ink of the invention as deposited in a TEM analysis grid.
  • the nanoparticles are dispersed, discrete, nanoparticles whose predominant shape and size are well controlled.
  • TEM Transmission Electron Microscopy
  • AFM Atomic Force Microscopy
  • DLS Dynamic Light Scattering
  • the TEM image shows a sample batch of silver nanoparticle ink comprising a mixture of silver nanoparticle plate shapes including triangular, truncated triangular and circular discs showing a narrow size distribution about a median of 24 nm in a polymer (polyvinyl alcohol) in aqueous solution.
  • the size of the silver nanoparticles can be controlled to range from about 5 nm to 100 nm and have a relatively narrow size distribution with aspect ratios which range from 1 to 10.
  • Samples of the ink were prepared, centrifuged down to remove the ink medium, and suspended in water before being dropped onto a TEM grid and allowed to dry.
  • Figure 18 displays an example of a histogram used to represent the diameter distribution of nanoparticle samples and determine their mean diameter, determined from TEM image analysis as described in Table 5.
  • Table 5 above gives a range of mean diameter of the nanoparticles and its standard deviation for seven different silver nanoparticle inks, determined from image analysis of TEM data.
  • Nanoparticle heights were measured from several different sections of the Si substrate, for seven different silver nanoparticle inks, and are shown in Table 6.
  • the effective sizes recorded for the silver nanoparticles using Dynamic Light Scattering (DSL) are much larger, by a factor of three to four, than those visible in the TEM analysis.
  • the ink medium which in this case is the polymer polyvinyl alcohol.
  • the nanoparticles are effectively suspended in the polymer medium so that the polymer inhibits the motion of the nanoparticles resulting in them appearing to move slower than they otherwise would for their true size (provided by AFM and TEM analysis) causing them to appear larger than they actually are.
  • the DSL diameter results are not so large as to indicate aggregation or agglomeration, which is also confirmed by the TEM analysis as evidenced in Figure 17.
  • Zeta potential theory states that nanoparticles with a zeta potential ⁇ -20mV or >+20mV are electrostatically stable.
  • the silver nanoparticle inks have been prepared and observed to remain stable over periods of years.
  • Table 7 displays the results for the zeta potential vs. concentration analysis on an ink. From these results we can see that as the ink is diluted down with water the zeta potential is increased.
  • the final zeta dependence study is that of its dependence on centrifugation of the ink, i.e. removing the polymer PVA ink medium.
  • Table 8 shows the results of this analysis. All spins on the centrifuge were preformed at 19.1k RCF at 4 0 C after each spin the sample was suspended in ImI of deionised water. A is the ink before any centrifugation, B is the ink after a 50 minute spin and then resuspended in ImI Deionised water and the subsequent measurements are after further subsequent 20 minute spins.
  • Example 14 Ink incorporating silver nanoplates with one predominant shape in an aqueous solution
  • an ink comprising silver nanoplates of one predominant shape, such as the nanoplates produced in accordance with the methods of Example 8 above and/or nanoplates having the physical properties described in Example 9 above.
  • a solution comprising 0.5 ml of 2.5 ⁇ lO ⁇ 2 M of trisodium citrate, 0.3 ml of 0.01 M sodium borohydride, 0.25 ml of 500 mg/1 poly(sodium 4-styrene sulfonate) of M W- 1,000,000 and 4.5 ml of deionised water was prepared and placed in a beaker with a magnetic stirrer, stirring rapidly. 3 ml of a 5XlO "4 M silver nitrate solution was added with a peristaltic pump at a rate of 2 ml/min while the mixture is stirring. This mixture is referred to as the seed mixture.
  • a 0.6 ml of 0.01 M ascorbic acid, 1 ml of the seed mixture and 50 ml of deionised water solution was prepared and placed in a beaker with a magnetic stirrer, stirring rapidly. 30 ml of a 5XlO "4 silver nitrate solution was added at a rate of 10 ml/min with a peristaltic pump. The final solution was topped with 5 ml of a 2.5x10 " trisodium citrate solution and 15 ml of deionised water. Referring to Fig. 24, the ink comprised triangular silver nanoplates having a main peak at 676nm.
  • Example 15 Ink incorporating silver nanoplates with two dominant shapes in an aqueous solution
  • an ink comprising silver nanoplates of two predominant shapes.
  • the nanoplates may be produced in accordance with Example 8 above. Some of the nanoplates, may posses the physical properties described in Example 9 above. Aqueous solution inks were made using a batch chemistry and a microfluidics process as described below.
  • a solution comprising 0.5 ml of 2.5xlO "2 M of trisodium citrate, 0.3 ml of 0.01 M sodium borohydride, 0.25 ml of 500 mg/1 poly(sodium 4-styrene sulfonate) of MW-1, 000,000 and 4.5 ml of deionised water was prepared and placed in a beaker with a magnetic stirrer, stirring rapidly. 3 ml of a 5XlO "4 M silver nitrate solution was added with a peristaltic pump at a rate of 2 ml/min while the mixture is stirring. This mixture is referred to as the seed mixture. The seed solution was aged for at least 2h prior to use.
  • the two dominant shapes in this case were nanoprisms and hexagonal nanoplates. It can be seen from the UV-VIS spectrum of Fig. 25A that the ink has two main peaks, one in the 425nm region corresponding to the hexagonal nanoplates and one in the 600nm region corresponding to the nanoprisms.
  • Microfluidic method The seed solution was prepared using a microfluidic chip as described in Examples 1 to 3 above. In this particular Example the seeds were synthesised in the presence of poly(sodium 4-styrene sulfonate) of M W- 1,000,000 at a concentration of 10 "4 M.
  • solution A AgNO 3 (5 mg) and TSC (7.4 mg) were dissolved in 100 mL H 2 O which is referred to as solution A.
  • a NaBH 4 (10 mM) solution was prepared in water referred to as solution B.
  • Solution A and solution B were pumped into a microfluidic chip at flow rates of 8 ml min 1 and of 1 ml min "1 respectively. A colour change form colourless to yellow was observed.
  • the seed solution was aged for at least 2h prior to use. The growth stage was performed using the batch wet chemistry method as described above.
  • This method produced silver nanoparticles which consisted of about 50-70% shaped nanoplates. Referring to Fig. 26 the two dominant shapes were hexagonal plates and nanoprisms. AFM measurements show mean heights to be in the range of 12-20 run for silver nanoplates in the ink.
  • Example 16 Ink incorporating silver nanoplates with two dominant shapes in an organic solution
  • inks comprising nanoplates of two dominant shapes in an organic solvent were produced according to the following method.
  • PVP Polyvinyl pyrrolidone
  • seed solution 100 ⁇ L
  • ascorbic acid 50 ⁇ L, 0.1 M
  • TSC 300 ⁇ L, 2.5 x 10 "2 M
  • AgNO 3 5 x 50 ⁇ L, 0.01 M
  • the sol was aged for 2h before being centrifuged at 13,200 rpm for 30 minutes and the pellets were redispersed in a variety of solvents namely methanol, ethanol and dimethylformamide.
  • nanoplates are dispersed in an organic solvent to form an ink that an appropriate polymer i.e. a polymer that is soluble in a organic solvent is used in the growth step.
  • an appropriate polymer i.e. a polymer that is soluble in a organic solvent is used in the growth step.
  • PVP was used.
  • Fig. 27 shows the UV-Vis absorption spectra of the original nanoplates and the nanoplates redispersed in methanol, water, ethanol and dimethlyformamide. Each spectrum displays three wavelength maxima in the 345nm, 420nm and 870nm regions.
  • an ink comprising a high loading concentration of silver nanoplates. It is possible to concentrate the nanoplates after completion of chemical reduction, stabilisation and if necessary functionalisation of the nanoplates.
  • the nanoplates were concentrated by centrifugation in a Sorvall RC 5C Plus centrifuge with a SLA 3000 rotor at 12,000 rpm (24,318 rcf) for 4 hours for a first pass and in an Eppendorf 5415R centrifuge with a F-45-24-11 rotor at 13,200 rpm (16,100 rcf) for 1 hour for a second pass.
  • the initial concentration and volume before centrifugation were, for example, 70 ppm in 1,800 ml respectively.
  • the supernatant volume collected was 1,680 ml giving an ink concentration and volume of 1,050 ppm and 120 ml (concentration factor: 15x).
  • the supernatant volume collected was 112 ml leaving a final ink with a concentration of 15,750 ppm and a volume of 8 ml (concentration factor: 15 ⁇ ).
  • Fig. 28 is a TEM image of the concentrated ink after the second pass.
  • concentrationAg (wt%) concentrationAg (ppm)x 100 / density wa ter (mg/1) is used to convert the concentration value in ppm.
  • the final concentration of the silver nanoplate produced in this example is therefore around 1.5 wt%. This value is more than an order of magnitude less than values of concentration of silver nanoparticle inks available in the market, such as Advanced Nano Products inks, which have concentrations in the region of 50 wt%.
  • the resistivity values of the silver nanoplate ink containing 1.5wt% silver perform very well for such low silver content inks. This is surprising and highly advantageous as the inks described herein have equal or superior conductivity values, i.e. equal or lower resistivity values compared to commercially available inks.
  • Example 18 - r neology of silver nanoplate ink as prepared by Example 15 above (micro fluidic production of seeds and batch growth) Viscosity and surface tension are the two most important properties of general inks.
  • additives such as polymers (e.g. polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP)) and cosolvent to water (e.g. diethylene glycol(DEG)) were incorporated in to the silver nanoplate ink.
  • PVA polyvinyl alcohol
  • PVP polyvinyl pyrrolidone
  • DEG diethylene glycol
  • diethylene glycol was used as a cosolvent to water.
  • a polyvinyl pyrrolidone stabilised silver nanoplate solution was prepared and centrifuged as described in example 17 above.
  • the recovered and concentrated silver nanoplate ink was dispersed by diethylene glycol (DEG) as a cosolvent to water to various concentrations in an ultrasonic bath to form the ink for testing.
  • DEG diethylene glycol
  • the preferred DEG to water weight ratio was found to be around 50 wt%.
  • the silver nanoplates may be functionalised or treated with chemical or biochemical agents, such as cytidine 5'-diphosphocholine, mercapto-hexanoic acid or mercapto-benzoic acid, to promote the formation of conductive paths.
  • chemical or biochemical agents such as cytidine 5'-diphosphocholine, mercapto-hexanoic acid or mercapto-benzoic acid.
  • Triangular silver nanoplates were produced by the two-step seed mediated method as described in Example 14 above. Post synthetic stabilization of the as prepared triangular silver nanoplates was carried out in a versatile manner which allows the surface chemistry of the nanoplates to be altered depending on their intended use. Triangular silver nanoprisms were functionalised with phosphochlorine as follows: 1 mL of a 30 mM freshly prepared aqueous solution of cytidine 5'-diphosphocholine (PC) was added to the triangular silver nanoplates prepared as described above. After an initial 30 minute incubation period, 500 ⁇ L of 25 mM trisodium citrate (TSC) was then added to sol for increased stabilization. The total volume of the sol is then brought to 10 mL with distilled water and the sol was left undisturbed at 4 0 C in the dark for over night incubation.
  • TSC trisodium citrate
  • TEM grids were prepared as follows: 1 mL of the PC functionalised nanoplates were centrifuged at 13,200 rpm at 4°C for 30 minutes. The colourless supernatant was carefully removed and the pellet was resuspended in 100 ⁇ L distilled H 2 O. 20 ⁇ L of this concentrated sol is then dropped onto a Formvar coated copper TEM grid. The excess liquid was allowed to evaporate overnight The grid was then placed in a storage box until TEM analysis was carried out. During the overnight drying process, the solvent is removed by evaporation. The TSNP are forced into closer contact as the volume of the solvent is reduced.
  • Silver nanoplate inks at concentrations of the order of I xIO 4 ppm were ink-jet printed on to a glass substrate using a MicroFab's JetLab II® Polymer/Solder/Ink Jetting System. Jetting parameters such as pulse frequency and pulse shape (rise, fall, dwell times) were investigated to obtain suitable drop velocities and sizes. Printing parameters such as droplet fall delays in combination with xy-stage movement were optimised to achieve smooth conductive tracks with high resolution.
  • the ink-jet printed line had a line width of approximately 150 ⁇ m and thickness of 96 run before and after annealing at 200 0 C for 6 minutes.
  • the resolution achieved was of the order of 10,000 dots per square inch (DPI).
  • the thickness of the silver nanoplate ink jet printed line was estimated using an Atomic Force Microscope (AFM) used in tapping mode.
  • Fig. 31 shows AFM top view images of the silver nanoplate ink printed line and features of the order of a couple of micrometers in size and around 500 run in height can be seen.
  • Fig. 32 shows the cross section analysis of the edge of the silver nanoplate ink jet printed on a glass substrate and the thickness of the printed line can be estimated to be around 96 nm from this analysis.
  • AFM Atomic Force Microscope
  • ultrafine ink jet printed conductive tracks can be manufactured using the high aspect ratio silver nanoplate inks which allows for less material (ink) to be used whilst providing for equal or superior electrical properties.
  • equal or superior conductivities can be achieved at lower metal content when a contact is achieved with such an ultrafine conductive path.
  • semi-transparent conductive tracks which can have applications in fields such as photovoltaics, can be manufactured using the silver nanoplate ink at such low thicknesses.
  • Increased percentage of shaped nanoplates at high aspect ratios over spherical nanoparticles provides increased surface contact area from the greater packing as indicated in Fig. 33 thereby providing improved conductive paths and conductivity of the printed inks, i.e. lowering the resistivity of the printed inks. This can in turn lead to lower percolation thresholds for shaped nanoplate based inks over spherical nanoparticle inks.
  • a l wt% concentrated silver nanoplate ink was printed on a DK test chip with gold metallisation and silicon nitride passivation, bridging some conductor lines as seen in Fig. 34.
  • the printed ink was annealed at 200°C for 6 minutes.
  • a 2-point probe resistance measurement of the annealed ink-jet printed silver nanoplate ink was performed to estimate its resistance.
  • the procedure used was a standard IV measurement, regularly calibrated with a short and an open value to negate the resistance of the probes.
  • One of the probe tips was at ground and connected to one end of the printed line and the other was connected to the other end of the printed line and had a voltage being swept from 0 - 1 OV in
  • bulk silver resistivity is in the region of 1.6 ⁇ lO "6 ⁇ .cm.
  • the silver nanoplate ink prepared in this example exhibits a resistivity, which is two orders of magnitude higher than that of bulk silver.
  • the silver content present in the silver nanoplate ink is two orders of magnitude lower than that of bulk silver.
  • Table 9 below shows that this resistivity result is an order of magnitude higher than samples 1 & 2 presented in this Table but the concentration of the silver nanoplate inks used in the example is more that an order of magnitude lower.
  • Example 22 Use of inks comprising silver nanoplates in photovoltaics
  • First generation solar cells are typically made using a silicon (Si) wafer and are the dominant technology in the commercial production of solar cells, accounting for more than 86% of the solar cell market, due to the omnipresence of silicon as semiconductor in electronics. In the case of current generation inorganic photovoltaic silicon may soon find the limit of its efficiency (30%). Attempts to improve the electrical efficiency using thin-film Si cells, so-called second generation devices, instead of wafer-thick have to date proven even poorer.
  • Si silicon
  • Silicon is a poor light absorber which is a strong limiting factor on solar cell efficiency. Enhancement of the absorption of sunlight using surface plasmon resonance has been demonstrated (e.g. K.R. Catchpole, S. Pillai and K.L. Lin, “Novel Applications for Surface Plasmons in Photovoltaics", 3 rd World Conference on Photovoltaic Energy Conversion - SIP- A7-09, 2714, 2003) wherein silver nanoparticles surface plasmons were used to enhance light trapping.
  • the enhancement was by a factor of 16 for light with a wavelength of 1050 nm, while when using wafers, the enhancement was by a factor of 7 for light with a wavelength of 1200 nm. To date only low quality silver nanoparticles and silver islands have been used for this purpose.
  • Third generation organic photovoltaic devices are limited by there capability to absorb only a small portion of the incident light. A major reason for this is that the semiconductor bandgap is too high.
  • a polymer with bandgap of 1.1 eV absorbs only 77 % of the solar radiation on Earth. Semiconducting polymers have bandgaps higher than 2.0 eV, limiting the possible absorption to less than 30%.
  • the use of the highly geometrically uniform silver nanoplate inks described herein which are spectrally tunable throughout the relevant solar spectral range and also tunable to semiconducting polymers and Si band gaps will provide significant advantages for efficiency enhancement.
  • a number of different silver nanoplate sizes with different peak wavelengths may be mixed to provide a broad spectral range as required.
  • the benefits which the high definition silver nanoplates can impart on photovoltaic devices include tunability of the silver nanoparticles to longer wavelengths from 550 nm to 1500 nm. They can also facilitate absorption, light trapping and guiding over a greater solar spectral range.
  • Optical tunability i.e. varying the localised surface plasmon resonance (LSPR) positions of the silver nanoplates can be achieved by tuning the geometry and the edge length of the nanoplates.
  • Ink solutions of silver nanoplates with different edge lengths and subsequent LSPR positions were investigated.
  • a series of silver nanoplates with increasing edge length from 1 1 nm to 197 nm were prepared.
  • the solution phase ensemble extinction spectra of the silver nanoplate solutions were acquired using a UV-Vis-NIR spectrometer with the peak LSPR resonances ranging from wavelengths of about 500 nm in the visible up to 1090 nm in the NIR.
  • the inks described herein can be tuned across the relevant sun spectral range to allow for enhanced solar light trapping.
  • the silver nanoparticles may be directly incorporated into organic devices as polymer composites enabling more intimate interactions than in the case of current isolated layer deposition.
  • the silver nanoparticles inherent conductive nature will contribute to the charge transport mechanisms of the photovoltaic devices thereby further improving device efficiency.
  • the thinness of the active organic layer is also an efficiency limiting factor: the typically low charge carrier and exciton mobility's require layer thickness in the order of 100 nm.
  • the very high scattering efficiency of the silver nanoplates will serve to increase the extinction coefficient of layers enabling increased efficiency at low thicknesses.
  • Fig. 36 (A) to (C) are schematics of photovoltaic devices incorporating silver nanoplate inks, where the active layer (120) can be and is not restricted to monocrystalline silicon (Si), polycrystalline Si, thin film Si, or organic materials (e.g. polythiophene derivatives and C 60 derivatives), where materials used for the semi-transparent top electrode (100) can be and are not restricted to titanium oxide or indium tin oxide, where the top intermediate layer (110) can incorporate hole blocking materials such as a metal oxide (e.g. zinc oxide) or a polyamine (e.g. polyethylenimine) and where the bottom intermediate layer (130) can incorporate electrically conductive materials such as metals (e.g. gold, silver, copper) or electrically conductive polymers (e.g. PEDOT).
  • Top (100) and bottom (140) electrodes are in electrical connection with an external load (150) so that electrons pass from the top electrode, through the load and to the bottom electrode.
  • Fig. 36A colour tunable, highly sensitive (shaped and high aspect ratio) silver nanoplates (121) can be used as active materials incorporated within an active layer of organic materials.
  • the silver nanoplates can be incorporated in for example a conductive polymer such as a fullerene derivative matrix and contribute either to the charge dissociation process involved, or the charge conduction mechanism or both, leading to increased efficiency.
  • Colour tunable, highly sensitive (shaped and high aspect ratio) silver nanoplates can be used as surface plasmon light trapping semi-transparent electrodes (101) as depicted in Fig. 36B.
  • a series of silver nanoparticles with optical tunability across the whole solar spectral range can be used to harness every incoming photon's energy and in turn waveguide this energy into the active layer (120).
  • Colour tunable, highly sensitive (shaped and high aspect ratio) silver nanoplates can be used as efficiently conductive bottom electrodes (141) as depicted in Fig. 36C.
  • the highly conductive nature coupled with the ultrafine feature of the silver nanoplate inks described herein can be used as to replace conventional conductive bottom electrodes, and contribute also to the conduction mechanism in the semi transparent top electrode (101) described in Fig. 36.
  • Example 23 Nanoplate inks as optical filters.
  • Optical tunability of silver nanoplate optical filter thin films across the visible and near-IR regions can be achieved by tuning the geometry and the edge length of the nanoplates used in the ink solutions.
  • Ink solutions of silver nanoplates with different edge lengths and subsequent LSPR positions were prepared.
  • Optical filter thin films were drop casted on glass substrates from shaped silver nanoplate ink solutions of various colours. UV-visible absorption spectroscopy and images of these optical filters, as seen in Fig. 37, shows how easily the filters colour can be tuned across the visible and near - IR regions using the ink described herein.
  • Example 24 Self Assembly of nanostructures A means of producing size and shape controlled nanoparticles and controlling their subsequent organisation into superstructures amenable to practical applications, are two of the primary goals of nanotechnology, the assembly of nanoparticles into well defined structures and architectures remains a challenges.
  • Branched linear arrays and linear chains with nanoscale diameters and lengths ranging up to tens of microns are among the structures that can be generated. Examples are shown in Fig. 19.
  • Fig. 20 shows the formation of a conductive track structure from the ink by two processes: (a) by the merging of nanoparticles (b) by the assembly of nanoparticles.
  • the features displayed are commonly observed and include extended chains, hexagonal ordered branching and an extensive degree of linearity. These assemblies have large aspect ratios with lengths up to 50 ⁇ m and diameters as low as 20 nm.
  • Fern-like formations with fractal geometry and capsules with villi projected surfaces as well as fishbone structures are examples of the dendritic patterns produced, spanning the micron to the millimetre scale. Examples are shown in Fig. 21.
  • nanoparticle shape in particular nanoparticle of anistropic shape as is the case of the silver nanoparticles used here, have been reported to facilitate in control the geometry of self-assembled arrays [reference B.A Korgel, D. Fitzmaurice, Adv. Mat. 10 (1998) 661].
  • inks comprising said silver nanoparticles and polyvinyl alcohol were drop- cast onto substrates including TEM grids, gold plated glass slides and silicon wafers and left to dry at room temperature. Imaging was carried out using both TEM and optical microscopes.
  • the silver nanoparticle inks spontaneously form of a range of extraordinarily dendritic patterns having fractal geometry on evaporation of the ink medium.
  • the images in Figure 21 illustrate a 2-D fern-like dendritic pattern with regular curved branching.
  • the dimensions of the dendrites produced range from tens of nanometers to several millimetres, clearly demonstrating the fractal nature of the patterns.
  • Microwave radiation may be used to promote growth producing dendritic patterns of even larger dimensions.
  • the nanoparticles can be aligned along the network: • Specific angles repeated e.g. round nanoparticles in supernatant @ 14Krpm, & larger nanoparticles remaining.
  • Conventional pigments in ink-jet inks contain particles in the size range of 100-400nm. In general, reducing the particle size to 50nm or less should show improved image quality and improved printhead reliability when compared to inks containing significantly larger particles.
  • the ink may be deposited on a substrate or material using one or more methods which may be selected from: ink jet printing; spin coating, screen printing, drop coating.
  • the deposition process conditions may be optimised to produce narrow line width conductive paths or structures, or optical films or coatings, or semi-transparent conductive films or coatings.
  • the ink may find applications in the formation of electrodes, or optics, or flat panel display devices, or optical filters, or active or passive layers on photovoltaic or solar cells, or active or passive layers in other electronic or opto-electronic devices.
  • the ink is of particular advantage in ink jet printing processes, because an ink jet process inherently does not allow the use of high-viscosity paste, and it is necessary to use a low- viscosity conductive ink including nanometer-scaled fine particles in such a process.
  • the ink to which in some preferred embodiments of the invention may be added a dispersant and/or other chemical or biological additives, is expelled from an ink jet nozzle to print a pattern.
  • heat treatment may be carried out to remove the solvent and, where present, the dispersant and in some embodiments may promote to assembly and/or binding of the remaining metal particles to each other.
  • a conductive path, wire, line or structure formed using the ink, for example as described above, or otherwise formed, will typically show sharply increased conductivity as the metal solid content in the ink increases above the percolation threshold, and also as the thickness of a printed metal line increases.
  • the silver nanoparticles exhibit properties related to shape, and size, including those related to the ratio of surface area to volume, which are different from larger, micron sized metals, enabling these shape and size controlled silver nanoparticle based inks to work where other more traditional inks have failed.
  • the ink may find application in high volume production of electronic circuitry.
  • Viscosity tests were performed using an AR-500 TA Instruments Rheometer for a series of these ink formulations in polyvinyl alcohol (PVA) based solutions.
  • a Carreau model was used to fit the data from the rheometer and extract the nanosilver ink's viscosity values.
  • Figure 22 shows that the viscosity of the PVA-based silver nanoparticle inks can be controllably varied as a function of PVA concentration.
  • An exponential fit to the data (dashed line) is used as a guide to the eye. This characteristic of the ink is of importance in industrial applications in deposition methods including spin-coating, ink-jet printing, screen printing.
  • FIG. 23 shows a typical nanosilver thin film using a 15% PVA-based solution and a 2,000 rpm spin speed.
  • a channel was made using a razor blade in order to estimate the thickness of the thin film with the help of the profile feature of the imaging software.
  • a 4.5 ⁇ m thick film was produced using the above mentioned parameters.

Abstract

L’invention concerne une encre comprenant une solution ou une suspension ou un mélange de nanoplaques d’argent dans un liquide, lesdites nanoplaques ayant une distribution de formes géométriques selon laquelle l’une des formes choisies parmi les suivantes est prédominante : forme de plaque circulaire; forme de plaque elliptique; forme de plaque triangulaire; forme de plaque hexagonale; autre forme de plaque polygonale plate.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010116345A1 (fr) * 2009-04-08 2010-10-14 National University Of Ireland, Galway Nanofeuillets d'argent
EP2522700A1 (fr) * 2011-05-11 2012-11-14 Saint-Gobain Glass France Pâte à imprimer pouvant être mise en suspension dans l'eau
WO2012171936A1 (fr) * 2011-06-14 2012-12-20 Bayer Technology Services Gmbh Formulation d'encre aqueuse contenant de l'argent pour la production de structures électro-conductrices et procédé d'impression à jet d'encre pour la production de telles structures électro-conductrices
JP2013108121A (ja) * 2011-11-18 2013-06-06 Noritake Co Ltd 金属ナノ粒子の製造方法
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US9572880B2 (en) 2010-08-27 2017-02-21 Sienna Biopharmaceuticals, Inc. Ultrasound delivery of nanoparticles
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US11826087B2 (en) 2010-08-27 2023-11-28 Coronado Aesthetics, Llc Compositions and methods for thermal skin treatment with metal nanoparticles

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US9203030B2 (en) * 2011-05-16 2015-12-01 Georgia Tech Research Corporation Recyclable organic solar cells on substrates comprising cellulose nanocrystals (CNC)
US9849512B2 (en) 2011-07-01 2017-12-26 Attostat, Inc. Method and apparatus for production of uniformly sized nanoparticles
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US9885001B2 (en) 2014-09-23 2018-02-06 Attostat, Inc. Fuel additive composition and related methods
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US11111396B2 (en) 2014-10-17 2021-09-07 C3 Nano, Inc. Transparent films with control of light hue using nanoscale colorants
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US11473202B2 (en) 2015-04-13 2022-10-18 Attostat, Inc. Anti-corrosion nanoparticle compositions
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US10147512B2 (en) 2015-12-09 2018-12-04 C3Nano Inc. Methods for synthesizing silver nanoplates and noble metal coated silver nanoplates and their use in transparent films for control of light hue
US10201571B2 (en) 2016-01-25 2019-02-12 Attostat, Inc. Nanoparticle compositions and methods for treating onychomychosis
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US11646453B2 (en) 2017-11-28 2023-05-09 Attostat, Inc. Nanoparticle compositions and methods for enhancing lead-acid batteries
US11018376B2 (en) 2017-11-28 2021-05-25 Attostat, Inc. Nanoparticle compositions and methods for enhancing lead-acid batteries
TWI698507B (zh) 2018-12-06 2020-07-11 財團法人工業技術研究院 改質的金屬奈米片及包括其之導電漿料
US20220275230A1 (en) * 2019-08-29 2022-09-01 Societe Bic Process of preparation of an aqueous gel ink with fixed color comprising silver nanoparticles
CN114177858B (zh) * 2021-12-13 2023-06-16 清氢(北京)科技有限公司 电催化剂宏量制备方法及宏量制备装置

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050074589A1 (en) * 2003-09-18 2005-04-07 Pan Alfred I-Tsung Printable compositions having anisometric nanostructures for use in printed electronics
WO2007065154A2 (fr) * 2005-12-02 2007-06-07 Nanodynamics Inc. Procede pour la fabrication de plaquettes d’argent
JP2007154292A (ja) * 2005-12-08 2007-06-21 Mitsubishi Materials Corp 銀粒子の製造方法及び得られた該銀粒子を含有する銀粒子含有組成物並びにその用途
WO2007118815A2 (fr) * 2006-04-13 2007-10-25 Ciba Holding Inc. Cellule photovoltaïque
WO2008018718A1 (fr) * 2006-08-07 2008-02-14 Inktec Co., Ltd. Procédé pour la préparation de nanoparticules d'argent et compositions d'encre d'argent les contenant
EP2045028A1 (fr) * 2007-09-26 2009-04-08 Fujifilm Corporation Nanoparticules métalliques, leur procédé de production, dispersion aqueuse, procédé de fabrication de circuit ou électrode imprimée, et carte ou dispositif de circuit imprimé
WO2009056401A1 (fr) * 2007-09-27 2009-05-07 Basf Se Nanoparticules de métal de transition isolables et redispersables, leur préparation et leur utilisation comme absorbeurs d'infrarouges

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080095705A1 (en) * 2004-11-09 2008-04-24 Virtanen Jorma A Methods and Devices for Facile Fabrication of Nanoparticles and Their Applications

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050074589A1 (en) * 2003-09-18 2005-04-07 Pan Alfred I-Tsung Printable compositions having anisometric nanostructures for use in printed electronics
WO2007065154A2 (fr) * 2005-12-02 2007-06-07 Nanodynamics Inc. Procede pour la fabrication de plaquettes d’argent
JP2007154292A (ja) * 2005-12-08 2007-06-21 Mitsubishi Materials Corp 銀粒子の製造方法及び得られた該銀粒子を含有する銀粒子含有組成物並びにその用途
WO2007118815A2 (fr) * 2006-04-13 2007-10-25 Ciba Holding Inc. Cellule photovoltaïque
WO2008018718A1 (fr) * 2006-08-07 2008-02-14 Inktec Co., Ltd. Procédé pour la préparation de nanoparticules d'argent et compositions d'encre d'argent les contenant
EP2045028A1 (fr) * 2007-09-26 2009-04-08 Fujifilm Corporation Nanoparticules métalliques, leur procédé de production, dispersion aqueuse, procédé de fabrication de circuit ou électrode imprimée, et carte ou dispositif de circuit imprimé
WO2009056401A1 (fr) * 2007-09-27 2009-05-07 Basf Se Nanoparticules de métal de transition isolables et redispersables, leur préparation et leur utilisation comme absorbeurs d'infrarouges

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010116345A1 (fr) * 2009-04-08 2010-10-14 National University Of Ireland, Galway Nanofeuillets d'argent
US9572880B2 (en) 2010-08-27 2017-02-21 Sienna Biopharmaceuticals, Inc. Ultrasound delivery of nanoparticles
US10537640B2 (en) 2010-08-27 2020-01-21 Sienna Biopharmaceuticals, Inc. Ultrasound delivery of nanoparticles
US11419937B2 (en) 2010-08-27 2022-08-23 Coronado Aesthetics, Llc Delivery of nanoparticles
US11826087B2 (en) 2010-08-27 2023-11-28 Coronado Aesthetics, Llc Compositions and methods for thermal skin treatment with metal nanoparticles
EP2522700A1 (fr) * 2011-05-11 2012-11-14 Saint-Gobain Glass France Pâte à imprimer pouvant être mise en suspension dans l'eau
WO2012152572A1 (fr) * 2011-05-11 2012-11-15 Saint-Gobain Glass France Pâte d'impression pouvant être mise en suspension dans l'eau
WO2012171936A1 (fr) * 2011-06-14 2012-12-20 Bayer Technology Services Gmbh Formulation d'encre aqueuse contenant de l'argent pour la production de structures électro-conductrices et procédé d'impression à jet d'encre pour la production de telles structures électro-conductrices
JP2013108121A (ja) * 2011-11-18 2013-06-06 Noritake Co Ltd 金属ナノ粒子の製造方法
EP2906286A4 (fr) * 2012-10-11 2016-07-20 Nanocomposix Inc Compositions et procédés de nanoplaque d'argent
US11583553B2 (en) 2012-10-11 2023-02-21 Nanocomposix, Llc Silver nanoplate compositions and methods
JP2016500679A (ja) * 2012-10-11 2016-01-14 ナノコンポジックス，インコーポレイテッド 銀ナノプレート組成物および方法
CN104822412A (zh) * 2012-10-11 2015-08-05 纳诺康波西克斯公司 银纳米片组合物及方法
EP3272388A1 (fr) * 2012-10-11 2018-01-24 Nanocomposix, Inc. Compositions et procédés de nanoplaques d'argent
CN108480620A (zh) * 2012-10-11 2018-09-04 纳诺康波西克斯公司 银纳米片组合物及方法
AU2020204436B2 (en) * 2012-10-11 2022-07-28 Coronado Aesthetics, Llc Silver nanoplate compositions and methods
US10688126B2 (en) 2012-10-11 2020-06-23 Nanocomposix, Inc. Silver nanoplate compositions and methods
AU2018241065B2 (en) * 2012-10-11 2020-04-02 Coronado Aesthetics, Llc Silver nanoplate compositions and methods
EP2851960A1 (fr) * 2013-09-20 2015-03-25 Kabushiki Kaisha Toshiba Élément de conversion photoélectrique
CN106029266B (zh) * 2014-03-28 2021-02-19 东洋铝株式会社 薄片状金属颜料及其制造方法，及其金属组合物和涂布物
CN106029266A (zh) * 2014-03-28 2016-10-12 东洋铝株式会社 薄片状金属颜料及薄片状金属颜料的制造方法
US10293406B2 (en) 2014-03-28 2019-05-21 Toyo Aluminium Kabushiki Kaisha Flaky metal pigment and method of manufacturing flaky metal pigment
WO2015146977A1 (fr) * 2014-03-28 2015-10-01 東洋アルミニウム株式会社 Flocons de pigment métallique et leur procédé de production
JPWO2015146977A1 (ja) * 2014-03-28 2017-04-13 東洋アルミニウム株式会社 フレーク状金属顔料、それを含むメタリック組成物および塗布物、ならびにフレーク状金属顔料の製造方法
EP3425012A4 (fr) * 2016-02-29 2019-01-09 FUJIFILM Corporation Composition d'encre, ensemble d'encres, procédé de formation d'image, et objet imprimé
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CN108699368A (zh) * 2016-02-29 2018-10-23 富士胶片株式会社 油墨组合物及图像形成方法
US10975257B2 (en) 2016-02-29 2021-04-13 Fujifilm Corporation Ink composition and image forming method
US11091662B2 (en) 2016-02-29 2021-08-17 Fujifilm Corporation Ink composition, ink set, image forming method, and printed matter
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